John Hartson says Benjamin Siegrist will be ‘really disappointed’ at how his Celtic career has panned out ahead of a possible exit. The 31-year-old is Celtic’s third-choice goalkeeper behind Joe Hart and Scott Bain – he has only made the bench once this season. After signing for Celtic on a high from Dundee United in 2022, there were big things expected of Benjamin Siegrist and what he could possibly bring. But fast forward to the present and he has only repped the Celtic jersey on just two occasions. John Hartson shared how he was once ‘performing every week’, but now he finds himself struggl…